Some online advertisers and Internet service providers use high-tech tracking programs to monitor the browsing habits of their customers. The tracking helps advertisers tailor their pitches, offering consumers the products and services that their Web use indicates they are most likely to want.

Ad companies like to describe it as a service to consumers. After all, they say, you are a lot less likely to object to those pop-up ads when they offer you something that you actually might want to buy.

But the rapid rise of "behavioral advertising," as the industry calls it, raises questions about online privacy, security and the right of customers to be informed. With online advertising, sometimes users know they're being tracked and sometimes they don't.

Even when the targeted customers find out about it and complain, often only the targeted advertising stops. The tracking of their Web use continues.

Customer backlash led to recent U.S. House and Senate hearings. Angry customers forced Charter Communications, the nation's fourth-largest cable operator, to pull out of a partnership in June with online ad company NebuAd. California-based NebuAd has the technical ability to build profiles of users' Web habits too detailed for many Charter customers' comfort.

NebuAd officials told members of Congress that customers' data is filed securely by numbers instead of names and behind digital firewalls of protection. The folks on Capitol Hill didn't sound reassured. The gist of their comments to NebuAd: Customers at least should know if they're being profiled, and have the option to block such tracking.

That was the message from Facebook members when the social networking site's Beacon program began to inject behaviorally targeted advertising into members' conversations late last year. The move ignited a users' revolt. Facebook retooled Beacon to let members withdraw from its clutches.

Last week, Yahoo did something similar, announcing that it will allow users to nix the targeted advertising on its Web sites.

But a Federal Trade Commission report offers a better idea: Have customers "opt in": Require Web sites, advertisers and Internet service providers to get permission from customers before tracking begins, not after.

"Opt-in" permission may already be required by the federal Telecommunications Act, says U.S. Rep. Ed Markey, chairman of the House Subcommittee on Telecommunications and the Internet. But the law's application is unclear because it has not been updated since it was passed in 1996. That's so last century. Google, YouTube and MySpace had not even been born.

So, let's clarify the law. Information on the Web is transforming society. Your information on the Web ... well, you should have some say about that.